The company is planning to further roll out its roof.

Tesla is about to get tough on its solar roof operations. In the company’s letter to shareholders on Wednesday, where it announced its fourth-quarter earnings for 2018, Tesla outlined plans to ramp up production, tweak the design and test its energy-gathering tiles in a broader range of conditions.

It’s a big step forward for the roof tiles, which have seen limited rollout since the first installations went live in April 2018. Tesla states that this year it aims to “ramp up” tile production “with significantly improved manufacturing capabilities.” This process will be based around the “design iterations and testing underway.” The company will continue to slowly install more tiles “to gather further learnings from our design changes,” while also learning more about the currently-planned installation process by putting the team through its paces. This will involve “implementing them in areas around the U.S. that are experiencing inclement weather.”

Tesla’s ramp-up comes amid a warmer overall solar market. Roberto Rodriguez Labastida, senior research analyst for Navigant, told Inverse last month that Tesla’s solar business reaching profitability, alongside competitors like Sunrun and Vivint Solar, means “it gives them freedom to choose their future strategy instead of relying on the will of investors.” Until now Tesla has only shipped to a select few customers like Tri Huynh and Amanda Tobler, both of whom live in California, and in May 2018 Reuters claimed the company had installed just 12 solar roofs.

The company will need to ensure its tiles can reach its lofty marketing claims. The tiles use a tempered glass three times stronger than asphalt or slate, a material Tesla is so confident about that it promises an “infinity” warranty on the tile itself and a 30-year warranty on the solar collection capabilities. While textured and smooth styles of tile have started shipping, Tesla has yet to roll out the more exotic Tuscan or slate styles.

Tesla may release more information about its planned rollout in its next quarterly earnings call, expected to take place in three months’ time.

At that point, it will have been nearly two-and-a-half years since CEO Elon Musk played solar salesman on the set of Desperate Housewives, promising a future where the electric car is powered by sunlight.

Elon Musk Explains The Necessity For Both Solar And Utility PowerMedia via Tesla